/*
 * Copyright (C) 2012 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package top.maxim.im.scan.camera;

import android.hardware.Camera;
import android.util.Log;

public final class OpenCameraInterface {

  private static final String TAG = OpenCameraInterface.class.getName();

  private OpenCameraInterface() {
  }

  
  /**
   * Opens the requested camera with {@link Camera#open(int)}, if one exists.
   *
   * @param cameraId camera ID of the camera to use. A negative value means "no preference"
   * @return handle to {@link Camera} that was opened
   */
  public static Camera open(int cameraId) {
    
    int numCameras = Camera.getNumberOfCameras();
    if (numCameras == 0) {
      Log.w(TAG, "No cameras!");
      return null;
    }

    boolean explicitRequest = cameraId >= 0;
    Camera camera;

    try{
      if (!explicitRequest) {
        // Select a camera if no explicit camera requested
        int index = 0;
        while (index < numCameras) {
          Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
          Camera.getCameraInfo(index, cameraInfo);
          if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_BACK) {
            break;
          }
          index++;
        }
        cameraId = index;
      }

      if (cameraId < numCameras) {
        Log.i(TAG, "Opening camera #" + cameraId);
        camera = Camera.open(cameraId);
      } else {
        if (explicitRequest) {
          Log.w(TAG, "Requested camera does not exist: " + cameraId);
          camera = null;
        } else {
          Log.i(TAG, "No camera facing back; returning camera #0");
          camera = Camera.open(0);
        }
      }
    }catch (Exception e){
      camera = null;
    }
    
    return camera;
  }
  
  
  /**
   * Opens a rear-facing camera with {@link Camera#open(int)}, if one exists, or opens camera 0.
   *
   * @return handle to {@link Camera} that was opened
   */
  public static Camera open() {
    return open(-1);
  }

}
